Solid titanium catalyst composition for production of an olefin polymer or copolymer

ABSTRACT

A solid titanium catalyst component for the production of olefin polymers or copolymers, comprising titanium, magnesium, halogen and an electron donor as essential ingredients, said component further comprising an inert liquid hydrocarbon in an amount of, based on the weight of said component, of about 1 to about 10% when said component has a uniformity coefficient of at least 4, and about 1 to about 25% when said component has a uniformity coefficient of less than 4.

This invention relates to an improved solid titanium catalyst componentwhich exhibits superior performance with good reproducibility when usedin producing an olefin polymer or copolymer (sometimes genericallyreferred to as an olefin polymer in this application) having a high bulkdensity and high stereospecificity and a low content of an undesirablefine powdery polymer.

More specifically, this invention relates to a solid titanium catalystcomponent for the production of olefin polymers or copolymers,comprising titanium, magnesium, halogen and an electron donor asessential ingredients, said component further comprising about 1 toabout 10%, based on the total weight of said component, of an inertliquid hydrocarbon.

It is well known, as disclosed in many publications to be exemplifiedhereinbelow, that a solid titanium catalyst component containingtitanium, magnesium, halogen and an electron donor as essentialingredients, when combined with an organometallic compound of a metal ofGroups I to III of the Mendeleejeff's periodic table, is useful in thehomopolymerization or copolymerization of olefins, especiallyalpha-olefins having at least 3 carbon atoms; or the copolymerization ofalpha-olefins having at least 3 carbon atoms and ethylene with orwithout diolefins to provide highly stereospecific polymers with highactivity.

The bulk densities or stereospecificity indices of polymers obtained bypolymerizing olefins with such catalysts by various polymerizationmethods such as solution polymerization, slurry polymerization orvapor-phase polymerization somewhat differ from each other, and thecatalytic activities of such catalysts also differ from each otherslightly. In many cases, the solid titanium catalyst component of highperformance can be obtained by treating the resulting solid carrier witha titanium compound in the liquid phase in the final stage ofpreparation of the catalyst component.

According to the conventional practice, the solid titanium catalystcomponent so obtained is well washed with, for example, an inert liquidhydrocarbon, and stored as a slurry in the inert hydrocarbon or as adried product until it is used for polymerization.

Noting that the performances of solid titanium catalyst componentsprepared from the same ingredients by the same means of preparationfrequently differ considerably from batch to batch, the presentinventors worked extensively to find the cause of difference.

Consequently, the present inventors have found that by drying the solidtitanium catalyst component so that a specified amount of the aforesaidliquid inert hydrocarbon remains therein, the final solid titaniumcatalyst component containing the specified amount of the inert liquidhydrocarbon can afford an olefin polymer having a high bulk density,high stereospecificity and a reduced content of an undesirable finepowdery polymer, and that the reproducibility of such a performance ofthe catalyst component is good, and marked industrial improvements canbe achieved.

This fact was unexpected because it was not known previously that theinert liquid hydrocarbon which the solid titanium catalyst component maycontain constitutes a factor which exerts a significant effect on theaforesaid properties of the catalyst component.

It has also been found that the aforesaid improvements can be achievedby adjusting the amount of the inert liquid hydrocarbon to about 1 toabout 10% based on the weight of the solid titanium catalyst componentwhen the catalyst component has a uniformity coefficient of at least 4,and to about 1 to about 25% on the same basis when the catalystcomponent has a uniformity coefficient of less than 4; and that as shownin comparative tests given hereinbelow, if the titanium catalystcomponent is dried to an extent such that the amount of the hydrocarbonretained exceeds the aforesaid lower limit, stereospecificity isreduced, or when drying is omitted or is insufficient with the amount ofthe retained hydrocarbon exceeding the upper limit, the resultingpolymer has a low bulk density and a large content of a fine powderypolymer.

It was quite unexpected that in spite of the fact that the aforesaidinert liquid hydrocarbon may be the same as the liquid hydrocarbon usedin polymerization, the aforesaid improvements can be achieved by usingthe solid titanium catalyst component containing the hydrocarbon in theabove-specified amount, and it is difficult to achieve theseimprovements when the amount of the hydrocarbon falls outside thespecified range.

It is an object of this invention therefore to provide a solid titaniumcatalyst component for olefin polymerization, which can achieve theaforesaid improvements.

The above and other objects and advantages of this invention will becomemore apparent from the following description.

The solid titanium catalyst component of this invention for use inolefin polymerization contains titanium, magnesium, halogen and anelectron donor as essential ingredients, and further comprises an inertliquid hydrocarbon in an amount, based on the weight of the titaniumcatalyst component, of about 1 to about 10% when the component has auniformity coefficient of at least 4, and about 1 to about 25% when thecomponent has uniformity coefficient of less than 4.

The amount of the inert liquid hydrocarbon in the titanium catalystcomponent of this invention is determined by gas chromatography after apredetermined amount of the titanium catalyst component is decomposedwith a large amount of alcohol.

The uniformity coefficient of the titanium catalyst component in thisinvention is determined by the photo-extinction method. Photo-extinctionmethod is described in Fine Particle Measurement, published by TheMacmillan Company, New York, P 75.

The titanium catalyst component is diluted with a liquid hydrocarbon toa concentration of about 0.3 g/l. The resulting suspension is put into ameasuring cell. Light from a slit is applied to the cell, and theintensity of the light which has been transmitted through the suspensionis continuously measured while particles of the catalyst component areprecipitating in the suspension. From the result, the particle sizedistribution of the catalyst component is determined. An integral curveof the particle size distribution is drawn by plotting the weightproportions on the ordinate and the particle diameters on the abscissaon the basis of the particle size distribution so determined. Theuniformity coefficient of the titanium catalyst component is defined asthe ratio of the particle diameter corresponding to a weight of 10% tothe particle diameter corresponding to a weight of 60% in the graph.Uniformity coefficient is described in Chemical Engineering, Oct. 13, 9(1969).

The solid titanium catalyst component of this invention comprisingtitanium, magnesium, halggen and an electron door as essentialingredients can be obtained by selecting a magnesium compound with orwithout halogen, or magnesium metal, a titanium compound with or withouthalogen, and an electron donor such that the resulting titanium catalystcomponent contains halogen, and intimately contacting the selectedingredients by such a means as heating or co-pulverization. Thehalogen/titanium mole ratio of the resulting catalyst componentpreferably exceeds about 4, and the catalyst component does notsubstantially permit liberation of the titanium compound by such asimple means as washing with hexane. The exact chemical structure of theresulting catalyst component is not known, but it is presumed that themagnesium atom and the titanium atom are firmly bonded to each otherhaving halogen in common. If desired, the solid titanium catalystcomponent may further comprise other metal atoms or elements such asaluminum, silicon, tin, boron, germanium, calcium, zinc and phosphorus,and functional groups. It may further include organic or inorganic inertsolid diluents such as LiCl, CaCC₃, BaCl₂, Na₂ CO₃, SrCl₂, B₂ O₃, Na₂SO₄, Al₂ O₃, SiO₂, TiO₂, NaB₄ O₇, Ca₃ (PC₄)₂, CaSO₄, Al₂ (SO₄)₃, CaCl₂,ZnCl₂, polyethylene, polypropylene, and polystyrene.

Organic acid esters or ethers are preferred as the electron donor.

Advantageously, the solid titanium catalyst component of this inventionhas a halogen/titanium mole ratio of more than 4, preferably at leastabout 5, more preferably at least about 8, for example up to about 100,a magnesium/titanium mole ratio of at least about 3, preferably about 5to about 50, an electron donor/titanium mole ratio of from about 0.2 toabout 6, preferably from about 0.4 to about 3, more preferably fromabout 0.3 to about 2, and a specific surface area of at least about 3 m²/g, preferably at least about 40 m² /g, more preferably at least about100 m² /g. Desirably, the X-ray spectrum of the complex shows it to beamorphous irrespective of the type of the starting magnesium compound,or to be much more amorphous than commercially available magnesiumdihalides.

Various means are known to form the solid titanium catalyst componentwhich contains titanium, magnesium, halogen and an electron donor beforecontrolling its inert liquid hydrocarbon content to the specified range,and any of such means can be used in this invention. Some of suchmethods for the preparation of the solid titanium catalyst component aredisclosed, for example, in Japanese Laid-Open Patent Publications Nos.108385/75 (corresponding to west German DOS No. 2,504,036), 126590/75(corresponding to U.S. Pat. No. 4,069,169), 20297/76 (corresponding towest German DOS No. 2504036), 28189/76 (corresponding to U.S. Pat. No.4,076,924), 64586/76, 92885/76, 127185/76, 136625/76, 8749/77(corresponding to west German DOS No. 2,701,647), 100596/77), 10459/77(corresponding to British Pat. No. 1,540,323), 147688/77 (correspondingto west German DOS No. 2,724,971), 151691/77 (corresponding to westGerman DOS No. 2,643,143), 2580/78 (corresponding to west German DOS No.2,729,196), 21093/78 (corresponding to west German DOS No. 2,735,672),30681/78 (corresponding to west German DOS No. 2,739,608),39991/78(corresponding to west German DOS No. 2,743,415), and 40098/78(corresponding to west German DOS No. 2,743,366).

Some specific embodiments of these means are described below.

(1) A magnesium compound, preferably a magnesium compound expressed bythe formula Mg(OR)_(n) X_(2-n) (in which R represents a hydrocarbongroup, for example an alkyl group having 1 to 18 carbon atoms, acycloalkyl group having 5 to 18 carbon atoms or an aryl group having 6to 18 carbon atoms, n is a number represented by O≦n≦2, and X representsa halogen atom, preferably chlorine, bromine or iodine), especiallypreferably magnesium chloride, is reacted with an electron donor or anadduct of the electron donor with a halogen-containing aluminum compound(the halogen-containing titanium compound and the electron donor mayform an adduct in advance, or the electron donor may form a complex withsuch a halogen-containing aluminum compound as an aluminum trihalide);or these compounds are strongly pulverized mechanically in the absenceor presence of a small amount of a hydrocarbon, a silicon compound, analuminum compound, an alcohol, a phenol, etc. The resulting reactionproduct or pulverized product, optionally treated further with a siliconcompound, an organoaluminum compound, etc. with or without an alcohol,is then further reacted with a titanium halide, preferably titaniumtetrachloride.

(2) A halogen-containing magnesium compound, preferably magnesiumchloride, is reacted with an active hydrogen-containing electron donorsuch as alcohols or phenols and an electron donor free from activehydrogen such as an organic acid ester or an organic acid halide, thenwith an organoaluminum compound or a silicon halide, and further with atitanium compound, preferably titanium tetrachloride.

(3) The product obtained in embodiment (1) or (2) is reacted furtherwith an electron donor and a titanium compound, preferably titaniumtetrachloride.

(4) The product obtained in embodiment (1) or (2) is reacted furtherwith an electron donor, a titanium compound, preferably titaniumtetrachloride, and an organoaluminum compound.

(5) A compound containing an organic magnesium compound is treated witha compound having a functional group such as a hydroxyl, ester orcarboxyl group or a halogen containing compound, and then treated with atitanium compound, preferably titanium tetrachloride, in the presence ofan electron donor.

The solid titanium catalyst component that can be formed by knownmethods can be purified by washing it with an inert liquid hydrocarbon.The term "inert hydrocarbon", as used in this application denotes ahydrocarbon which does not markedly degrade the performance of catalyst.Examples of such a hydrocarbon include aliphatic hydrocarbons such asn-pentane, isopentane, n-hexane, isohexane, n-heptane, n-octane,iso-octane, n-decane, n-dodecane, kerosene, and liquid paraffin;alicyclic hydrocarbons such as cyclopentane, methylcyclopentane,cyclohexane and methylcyclohexane; and aromatic hydrocarbons such asbenzene, toluene, xylene and cymene. These hydrocarbons may be used as amixture of at least two.

In order to obtain a titanium catalyst component having a degree ofuniformity of less than 4, it is preferred to use a method whichcomprises narrowing the particle size distribution of a magnesiumcompound, and then reacting such a magnesium compound with a titaniumcompound which is liquid under the reaction conditions, or a methodwhich comprises reacting a liquid magnesium compound and a liquidtitanium compound under conditions that particles having a narrowparticle size distribution are precipitated. For example, such a solidtitanium catalyst component can be prepared by the techniques disclosedin Japanese Laid-Open Patent Publications Nos. 38590/77, 146292/78 and41985/79, and Japanese Patent Applications Nos. 43002/79, 43003/79 and75582/79. Several examples of such techniques are described belowbriefly.

(1) An oxygen-containing magnesium compound, or a complex of a magnesiumcompound and an electron donor, having a particle diameter of about 1 toabout 200 microns and a uniformity coefficient of less than about 4,optionally pre-treated with an electron donor and/or a reagent such asan organoaluminum compound or halogen-containing silicon compound, isreacted with a titanium halide which is liquid under the reactionconditions, preferably titanium tetrachloride.

(2) A magnesium compound in the liquid state having no reducing abilityis reacted with a liquid titanium compound in the absence or presence ofan electron donor to precipitata a titanium catalyst component having aparticle diameter of about 1 to about 200 microns and a uniformitycoefficient of less than about 4.

(3) The product obtained in (2) above is reacted with a titaniumcompound.

(4) The product obtained in (1) or (2) is reacted with an electron donorand a titanium compound.

(5) The product obtained in (1) or (2) is reacted with an electrondonor, a titanium compound and an organoaluminum compound.

Examples of the magnesium compound used in the preparation of thetitanium catalyst component having a uniformity coefficient of less than4 include magnesium oxide, magnesium hydroxide, hydrotalcite, carboxylicacid salts of magnesium, alkoxymagnesiums, aryloxymagnesiums,alkoxymagnesium halides, aryloxymagnesium halides, magnesium dihalides,and the reaction products between organic magnesium compounds andsilanols, siloxanes, halosilanes, etc.

The solid titanium catalyst component of this invention can be obtained,for example, by drying the wet component formed in the aforesaid mannerby washing with an inert liquid hydrocarbon. When the aforesaidcomponent has a uniformity coefficient of at least 4, the final productcan be obtained by drying it such that the content of the inert liquidhydrocarbon is about 1 to about 10%, preferably about 1 to about 6%,based on the weight of the component.

If the aforesaid drying is omitted, or the drying resulted in a largercontent of the inert liquid hydrocarbon than the specified upper limit,an olefin polymer obtained by, for example, slurry polymerization orvapor-phase polymerization, does not have an increased bulk density, andthe amount of a fine powdery polymer increases, and moreover, thereproducibility of the quality of the resulting polymer is poor. Bydrying the resulting titanium catalyst component such that its contentof inert liquid hydrocarbon is within the specified range, there can beobtained a solid titanium catalyst component, which when used in thepolymerization of olefins, can give a polymer having an increased bulkdensity with a reducted amount of a fine powdery polymer and a goodreproducibility of the quality of the resulting polymer. Furthermore,the loss of the polymer decreases in block copolymerization in propylenepolymerization, and a polymer of high quality can be produced. Moreover,the catalyst component is easier to transport or store. When the dryingis carried out such that the content of the inert liquid hydrocarbondecreases beyond the specified lower limit, the stereospecificity indexof an olefin polymer obtained by the stereospecific polymerization ofolefin using the resulting titanium catalyst component is reduced.

The solid titanium catalyst component of this invention may be stored assuch, preferably in an inert atmosphere, such as a nitrogen atmosphere,until it is used for polymerization. If desired, it may be againsuspended in an inert liquid hydrocarbon and stored in this state. Whenit is stored for an excessively long period of time, the effect ofdrying may be lost. Accordingly, it should be used for polymerization asearly as possible, even when it is stored as suspended in an inertliquid hydrocarbon. For example, when the titanium catalyst componenthas been dried to such an extent that its content of the hydrocarbon isabout 1 to about 6%, its performance does not change for about 10 daysat room temperature. When the drying is done to such an extent that thecontent of the hydrocarbon is about 6 to about 10%, the performance ofthe resulting catalyst component begins to decrease when it ismaintained at room temperature for about 2 days. In such a case, thecatalyst component may be again suspended in the inert liquidhydrocarbon and again dried to adjust its content to the specifiedrange, before it is used for polymerization.

When the uniformity coefficient of the aforesaid catalyst component isless than 4, it is dried until the amount of the liquid hydrocarbonreaches about 1 to about 25%, preferably about 1 to about 20%, based onthe weight of the component. When no drying is done, or the drying isinsufficient so that the amount of the liquid hydrocarbon exceeds thespecified upper limit, the catalyst particles are liable to undergoagglomeration during transportation or storage, and are difficult todischarge from a catalyst reservoir. By drying the catalyst component tothe specified extent, it can be more easily transported or stored.

The drying treatment is carried out preferably under relatively mildtemperature conditions. For example, it is carried out at a temperatureof not more than about 80° C., preferably about 0° C. to about 60° C.,in an atmosphere of an inert gas. Temperatures in excess of about 80° C.tend to cause a reduction in polymerization activity in contrast to thecase of performing the drying treatment at temperatures lower than about80° C. Accordingly, drying at temperatures lower than about 80° ispreferred. On the other hand, too low a drying temperature, for exampletemperatures below about 0° C., is not practical because it will prolongthe treating time to no advantage.

The drying time depends upon various operating conditions such astemperature. Drying is carried out until the content of the inert liquidhydrocarbon in the solid titanium catalyst component reaches the valueswithin the specified range. Generally, the drying time is from about 15minutes to about 100 hours, preferably from about 30 minutes to about 48hours. The pressure maintained during the drying of the solid titaniumcatalyst component is not critical so long as it is lower than thesaturated pressure of the liquid held in the catalyst component. Forexample, the drying can be carried out at atmospheric pressure orreduced pressure. If the drying temperature is as low as roomtemperature, it is advantageous to perform the drying under reducedpressure so as to promote removal of the inert liquid medium.

Drying of the solid titanium catalyst component may be carried out in anatmosphere of an inert gas. The use of nitrogen is preferred for thispurpose.

Drying of the solid titanium catalyst component in this invention may becarried out in an apparatus having a specification suitable for theoperation, for example a moving bed dryer such as a horizontal stirreddryer, a rotary drum-type dryer or a vertical stirred dryer. A fixed beddryer through which an inert gas flows may also be used, but the movingbed-type is advantageous because the drying time is shorter.Advantageously, the solid titanium catalyst component to be subjected tothe drying step is moderately deprived of the inert liquid hydrocarbonbefore the drying treatment. Filtration, centrifugation, precipitatingseparation using a siphon, etc. may be used to remove the hydrocarbonprior to the drying treatment.

The halogen which constitutes the solid titanium catalyst component ofthis invention is fluorine, chlorine, bromine, iodine or mixturesthereof. Chlorine is preferred.

The electron donor used in the production of the solid titanium catalystcomponent includes, for example, oxygen-containing electron donors suchas alcohols, phenols, ketones, aldehydes, carboxylic acids, organic orinorganic acid esters, ethers, acid amides and acid anhydrides, andnitrogen-containing electron donors such as ammonia, amines, nitrilesand isocyanates.

Specific examples of these electron donors are alcohols having 1 to 18carbon atoms such as methanol, ethanol, propanol, pentanol, hexanol,octanol, dodecanol, octadecyl alcohol, benzyl alcohol, phenethylalcohol, cumyl alcohol and isopropyl benzyl alcohol; phenols having 6 to15 carbon atoms and optionally containing a lower alkyl group, such asphenol, cresol, xylenol, ethylphenol, propylphenol cumylphenol andnaphthol; ketones having 3 to 15 carbon atoms such as acetone; methylethyl ketone, methyl isobutyl ketone, acetophenone and benzophenone;aldehydes having 2 to 15 carbon atoms such as acetaldehyde,benzaldehyde, tolualdehyde and naphthoaldehyde; organic acid estershaving 2 to 18 carbon atoms such as methyl formate, methyl acetate,ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexylacetate, ethyl propionate, methyl butyrate, ethyl valerate, methylchloroacetate, ethyl dichloroacetate, methyl methacrylate, ethylcrotonate, ethyl cyclohexanecarboxylate, methyl benzoate, ethylbenzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexylbenzoate, phenyl benzoate, benzyl benzoate, methyl toluate, ethyltoluate, amyl toluate, ethyl ethylbenzoate, methyl anisate, ethylanisate, ethyl ethoxybenzoate, γ-butyrolactone, δ-valerolactone,coumarine, phthalide and ethylene carbonate; inorganic acid esters suchas ethyl silicate and ethylethoxysilane; acid halides such as acetylchloride, benzyl chloride, toluoyl chloride and anisoyl chloride; ethershaving 2 to 20 carbon atoms such as methyl ether, ethyl ether, isopropylether, butyl ether, amyl ether, tetrahydrofuran, anisole and diphenylether; acid amides such as acetamide, benzamide and toluamide; aminessuch as methylamine, ethylamine, diethylamine, tributylamine,piperidine, tribenzylamine, aniline, pyridine, picoline and tetramethylethylene diamine; and nitriles such as acetonitrile, benzonitrile andtolunitrile. Two or more of these electron donors may be used incombination.

Preferred electron donors to be included in the titanium catalystcomponent as an essential ingredient are those not having activehydrogen, such as organic or inorganic acid esters, ethers, ketones,tertiary amines, acid halides and acid anhydrides. The organic acidesters and ethers are especially preferred. Of these, aromaticcarboxylic acid esters, and alkyl-containing ethers are most preferred.Typical examples of the preferred aromatic carboxylic acid estersinclude aromatic carboxylic acid esters having 8 to 18 carbon atoms,especially lower alkyl or alkoxy esters of benzoic acid, lower alkylbenzoic acids and lower alkoxybenzoic acids. Preferably, these loweralkyl or alkoxy esters have 1 to 4 carbon atoms, especially 1 or 2carbon atoms. Suitable alkyl-containing ethers are those having 4 to 20carbon atoms such as diisoamyl ether and dibutyl ether.

The solid titanium catalyst component for olefin polymerization inaccordance with this invention can be advantageously utilized forpolymerization of olefins when combined with organometallic compounds ofmetals of Groups I to III of the periodic table, especiallyorganoaluminum compounds.

Organoaluminum compounds containing one Alcarbon bond at least in themolecule. Examples are (i) organoaluminum compounds of the generalformula R¹ _(m) Al(OR²)_(n) H_(p) X_(q) (wherein each of R¹ and R²represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1to 4 carbon atoms, for example, an alkyl, cycloalkyl or aryl group andmay be identical or different, X represents halogen, m is a numberrepresented by O<m≦3, n is a number represented by O<n≦3, p is a numberrepresented by O<p≦3, and q is a number represented by O<q≦3, with theproviso that m+n+p+q=3); and (ii) complex alkylated products of metalsof Group I and aluminum, as represented by the general formula M¹ AlR¹ ₄(wherein M¹ represents Li, Na or K, and R¹ is as defined above).

Examples of the organoaluminum compounds that fall within the category(i) include those of the general formula R¹ _(m) Al(OR²)_(3-m) whereinR¹ and R² are as defined above, and m is preferably a number representedby 1.5≦m≦3; those of the general formula R¹ _(m) AlX_(3-m) wherein R¹ isas defined above and X is halogen, and m is preferably O<m<3; those ofthe general formula R¹ _(m) AlH_(3-m) wherein R¹ is as defined above,and m is a number preferably a number represented by 2≦m<3; and those ofthe general formula R¹ _(m) Al(OR²)_(n) X_(q) wherein R¹ and R² are asdefined above, X is halogen, O<m≦3, O≦n<3, O≦q<3, and m+n+q=3.

Specific examples of the aluminum compounds (i) include trialkylaluminums such as triethyl aluminum and tributyl aluminum; trialkenylaluminums such as triisoprenyl aluminum; dialkyl aluminum alkoxides suchas diethyl aluminum ethoxide and dibutyl aluminum butoxide; alkylaluminum sesquiethoxide and butyl aluminum sesquibutoxide; partiallyalkoxylated alkyl aluminums having an average composition R¹ ₂.5Al(OR²)₀.5 ; partially halogenated alkyl aluminums, for example, dialkylaluminum halogenides such as diethyl aluminum chloride, dibutyl aluminumchloride and diethyl aluminum bromide, alkyl aluminum sesquihalogenidessuch as ethyl aluminum sesquichloride, butyl aluminum sesquichloride andethyl aluminum sesquibromide, and alkyl aluminum dihalogenides such asethyl aluminum dichloride, propyl aluminum dichloride and butyl aluminumbromide; partially hydrogenated alkyl aluminums, for example dialkylaluminum hydrides such as diethyl aluminum hydride and butyl aluminumhydride, and alkyl aluminum dihydrides such as ethyl aluminum dihydrideand propyl aluminum dihydride; and partially alkoxylated and halogenatedalkyl aluminums such as ethyl aluminum ethoxy chloride, butyl aluminumbutoxy chloride and ethyl aluminum ethoxybromide. Organoaluminumcompounds in which two or more aluminum atoms are bonded through anoxygen or nitrogen atom, which are similar to the compounds (i), mayalso be used. Examples of these compounds are (C₂ H₅ )₂ AlOAl(C₂ H₅),(C₄ H₉)₂ AlOAl(C₄ H₉)₂, and (C₂ H₅)₂ AlNAl(C₂ H₅)₂.

Examples of the compounds that fall within the category (ii) are LiAl(C₂H₅)₄ and LiAl(C₇ H₁₅)₄.

Among the above compounds, trialkyl aluminums and mixtures of trialkylaluminums and alkyl aluminum halides are preferred.

The solid titanium catalyst component containing an inert liquidhydrocarbon in accordance with this invention can be used advantageouslyin the polymerization or copolymerization of olefins. For example, theolefins are those having 2 to 8 carbon atoms such as ethylene,propylene, 1-butene, 4-methyl-1-pentene and 1-octene. These olefins maybe subjected not only to homopolymerization, but also to randomcopolymerization or block copolymerization. In the copolymerization,polysaturated compounds such as conjugated or non-conjugated dienes maybe selected as comonomers. Particularly, by utilizing the catalystcomponent of this invention in the polymerization or copolymerization ofalpha-olefins having at least 3 carbon atoms, the copolymerization ofthese with dienes, or copolymerization of these with not more than 10mole% of ethylene, polymers having high stereospecificity can beobtained in high yields with good reproducibility.

The polymerization can be performed either in the liquid phase or in thevapor phase. When it is carried out in the liquid phase, an inert liquidhydrocarbon solvent such as hexane, heptane and kerosene may be used asa reaction medium, but the olefin itself may be used as a reactionmedium. In the liquid-phase polymerization it is preferred to use thesolid titanium catalyst component of this invention in an amount ofabout 0.0001 to about 1 millimole, calculated as titanium atom, and anorganoaluminum compound in an amount of about 0.1 to about 50millimoles, calculated as aluminum atom, both per liter of liquid phase,and to adjust the aluminum/titanium atomic ratio to about 1:1 to about1000:1. A molecular weight controlling agent such as hydrogen may beused in the polymerization process. To control the stereospecificity ofalpha-olefins having at least 3 carbon atoms, the polymerization mayalso be carried out in the co-presence of an ethylene glycol derivative(e.g., ethylene glycol monomethyl ether), an ether, an amine, asulfur-containing compound, a nitrile, an organic or inorganic ester, anacid anhydride, an alcohol, etc. The presence of an aromatic carboxylicacid ester such as a benzoate, p-toluate or anisate as exemplifiedhereinabove with regard to the preparation of the titanium catalystcomponent is preferred. These compounds may be used in the form of anadduct with the organoaluminum compound. The effective amount of theaforesaid additional compound is usually about 0.01 to about 2 moles,preferably about 0.1 to about 1 mole, per mole of the organoaluminumcompound.

The polymerization temperature for olefins is preferably about 20° C. toabout 200° C., more preferably about 50° C. to about 180° C. Thereaction pressure is from atmospheric pressure to about 50 kg/cm²,preferably an elevated pressure of from about 2 to about 20 kg/cm². Thepolymerization can be carried out in any of batchwise, semi-continuousand continuous modes. The polymerization may, if desired, be carried outin two or more stages in which the reaction conditions and/or thereaction zones are different.

The solid titanium catalyst component of this invention is especiallysuitable for the production of highly stereospecific polymers of highbulk densities in high yields from alpha-olefins having at least 3carbon atoms. Since the amount of a fine powdery polymer formed issmall, the solid catalyst component can be used with commercialadvantage.

The following examples illustrate the present invention in more detail.

EXAMPLE 1

Preparation of a Ti-containing catalyst component:

Under a nitrogen atmosphere, 20 g of MgCl₂, 5.25 g of ethyl benzoate and3 ml of dimethylpolysiloxane (viscosity 20 c.s.) were fed into astainless steel (SUS-32) ball mill vessel having an inside diameter of100 mm and containing 2.8 kg of stainless steel (SUS-32) balls eachhaving a diameter of 15 mm, and were contacted under mechanicallypulverizing conditions for 24 hours at an acceleration of impact of 7G.Fifteen (15) grams of the resulting pulverized product was suspended in150 ml of titanium tetrachloride, and contacted at 80° for 2 hours withstirring. The solid portion was collected by filtration. Furthermore,150 ml of titanium tetrachloride was added to the solid portion on thefilter, and they were stirred at 80° C. for 1 hour. The mixture wasfiltered, and thoroughly washed with fresh hexane. The resultingTi-containing catalyst component had an average particle diameter of 14microns, and a uniformity coefficient of 4.55.

Drying of the Ti-containing catalyst component:

A suspension of 10 g of the resulting Ti-containing catalyst componentin 30 ml of hexane as an inert liquid hydrocarbon was taken into a 300ml. flask which had been purged fully with nitrogen. The flask wasdipped in an oil bath maintained at 80° C., and a stream of N₂ waspassed through it for 5 hours to dry the titanium catalyst component.The resulting solid titanium catalyst component contained 1.7% by weightof Ti; 64.5% by weight of Cl, 20.6% by weight of Mg, 7.1% by weight ofethyl benzoate, and 4.8% by weight of hexane.

Polymerization:

A 2-liter autoclave was charged with 0.75 liter of hexane, and theinside of the autoclave was fully purged with propylene. The inside ofthe autoclave was heated to 55° C., and then 3.75 millimoles of triethylaluminum, 1.25 millimoles of methyl toluate and 0.0225 mg-atom,calculated at Ti atom, of the resulting Ti catalyst component wereadded. H₂ was added in an amount of 300 N ml, and immediately then, thetemperature of the polymerization system was raised. Propylene waspolymerized therein at 70° C. for 4 hours while maintaining the pressureat 7 kg/cm². G. After the polymerization, the solid portion wascollected by filtration. There was obtained 237.8 g of white powderypolypropylene having a boiling n-heptane extraction residue of 96.2%, amelt flow index (MI) of 4.6 g/10 min. and an apparent density of 0.33g/ml. There was obtained 14.4% by weight of a fine powdery polymerhaving a particle diameter of less than 105 microns. Concentrating theliquid phase afforded 8.6 g of a solvent-soluble polymer.

COMPARATIVE EXAMPLE 1

Propylene was polymerized under the same conditions as in Example 1except that the titanium catalyst component obtained in Example 1 wasused as a hexane suspension without subjecting it to the drying step.There was obtained 173.7 g of a white powdery polymer having a boilingn-heptane extraction residue of 97.0%, a melt flow index of 3.0. and anapparent density of 0.20 g/ml. There was obtained 25.5% by weight of afine powdery polymer having a particle diameter of less than 105microns. Concentrating the liquid phase afforded 5.5 g of asolvent-soluble polymer.

COMPARATIVE EXAMPLE 2

Propylene was polymerized under the same conditions as in Example 1except that the titanium catalyst component obtained in Example 1 wasdried under a stream of nitrogen gas at 40° C. for 2 hours to a hexanecontent of 12.5% by weight prior to use in the polymerization. There wasobtained 266.2 g of a white powdery polymer having a boiling n-heptaneextraction residue of 95.2% by weight, a melt flow index of 6.2 and anapparent density of 0.27 g/ml. There was obtained 19.5% by weight of afine powdery polymer having a particle diameter of less than 105microns. Concentrating the liquid phase afforded 9.8 g of asolvent-soluble polymer.

COMPARATIVE EXAMPLE 3

The titanium catalyst component obtained in Example 1 was washed withhexane, and then dried at 2 mmHg for 3 hours. The hexane content of thedried product was 0.1% by weight.

Polymerization:

Propylene was polymerized under the polymerization conditions shown inExample 1 using the resulting titanium catalyst component. There wasobtained 225.8 g of a white powdery polymer having a boiling n-heptaneextraction residue of 94.1%, an apparent density of 0.36 g/ml and a meltflow index of 5.3. There was obtained 10.6% by weight of a fine powderypolymer having a particle diameter of less than 105 microns.Concentrating the solvent layer afforded 12.7 g of a solvent-solublepolymer.

EXAMPLE 2

The same titanium catalyst component as obtained in Example 1 was driedfirst at 70° C. for 30 minutes until it became a mud, and then the mudwas maintained at 50° C. for 1.5 hours. The resulting catalyst componentwas found to contain 4.2% of hexane.

Propylene was polymerized under the same conditions as in Example 1using the resulting catalyst component.

The results are shown in Table 1.

EXAMPLE 3

A titanium catalyst component was prepared in the same way as in Example1 except that 8.6 g of ethyl o-toluate was used instead of 5.25 g ofethyl benzoate, and dimethylpolysiloxane was not used. The resultingtitanium catalyst component had an average particle diameter of 13.5microns and a uniformity coefficient of 4.6.

Drying:

A mixture of 7 g of hexane and 11 g of the resulting solid titaniumcatalyst component was dried at 25° C. for 30 minutes under a pressureof 10 mmHg. The resulting solid contained 1.9% by weight of Ti, 18.0% byweight of Mg, 60.0% by weight of Cl, 8.5% by weight of ethyl benzoateand 3.1% by weight of hexane.

Polymerization:

Propylene was polymerized under the same conditions as in Example 1. Theresults are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                                                          Amount                                           Amount                       of a fine                                        of a                         powdery Amount                                   white    Boiling             polymer of a                                     powdery  n-hept- Appa-       with a size                                                                           solvent-                            Ex-  poly-    ane     rent  MI    of less than                                                                          soluble                             am-  mer      residue density                                                                             (g/10 105 microns                                                                           polymer                             ple  (g)      (%)     (g/ml)                                                                              min.) (wt. %) (g)                                 ______________________________________                                        2    215.7    95.2    0.35  6.9   14.3     8.2                                3    279.2    94.1    0.36  4.4   11.5    12.8                                ______________________________________                                    

EXAMPLE 4

Preparation of a titanium catalyst component:

Anhydrous magnesium chloride (4.79 g), 25 ml of n-decane and 18.3 ml of2-ethyl hexanol were heat-treated at 130° C. for 2 hours to form auniform solution. Then, 0.84 ml of ethyl benzoate was added. Thesolution was added dropwise with stirring over 20 minutes to 200 ml oftitanium tetrachloride cooled at 0° C. The temperature was graduallyraised, and then 1.39 ml of ethyl benzoate was added at 80° C. Themixture was stirred at 80° C. for 2 hours. The solid portion wascollected by filtration, and again suspended in 100 ml of titaniumtetrachloride. The suspension was heated at 90° C. for 2 hours, and thenthe solid was collected by filtration. The solid was thoroughly washedwith purified hexane until no free titanium compound was detected in thewashing.

The resulting titanium catalyst component contained 3.4% by weight ofTi, 20.0% by weight of Mg, 59.0% by weight of Cl and 16.6% by weight ofethyl benzoate, and had a spherical particle shape, an average particlediameter of 5 microns, and a uniformity coefficient of 1.34.

Drying of the titanium catalyst component:

A suspension of 3 g of the titanium catalyst component in 30 ml ofhexane was fed into a 300 ml flask fully purged with nitrogen, and thenmaintained at 25° C. The flask was dipped in a bath, and nitrogen waspassed through it for 50 minutes. The resulting dry titanium catalystcomponent was a solid powder having good flowability. By analysis, thesolid was found to contain 16.6% by weight of hexane.

Polymerization:

A 2-liter autoclave was charged with 0.75 liter of hexane, and theinside of the autoclave was purged fully with propylene. Thepolymerization system was heated to 68° C., and 0.50 millimole oftriethyl aluminum, 0.25 millimole of ethyl aluminum sesquichloride, 0.15millimole of methyl toluate, and 0.015 mg-atom, calculated as Ti atom,of the resulting titanium catalyst component were fed into theautoclave. H₂ was introduced in an amount of 400 ml, and propylene wascharged into it continuously. Propylene was polymerized at 70° C. for 2hours while maintaining the pressure at 7 kg/cm².G. After thepolymerization, the solid component was collected by filtration. Therewas obtained 197.0 g of white powdery polypropylene having a boilingn-heptane extraction residue of 97.4%, a melt flow index of 4.1 and anapparent density of 0.38 g/ml. The polymer was in the form of sphericalparticles having an average particle diameter of 120 microns and auniformity coefficient of 1.4. Concentrating the liquid phase afforded1.7 g of a solvent-soluble polymer.

EXAMPLE 5

In the preparation of the titanium catalyst component in Example 4, thedrying was performed at 50° C. for 15 minutes to afford a solid titaniumcatalyst component having a hexane content of 11.6% by weight.

Polymerization:

Propylene was polymerized under the same conditions as in Example 4. Theresults are shown in Table 2.

EXAMPLE 6

In the preparation of the titanium catalyst component in Example 4,heptane was used instead of the hexane, and drying was performed at 30°C. for 4 hours under a stream of N₂. By analysis, the solid catalystcomponent was found to have a heptane content of 18.6% by weight.

Polymerization:

Propylene was polymerized under the same conditions as in Example 4. Theresults are shown in Table 2.

EXAMPLE 7

Synthesis of spherical MgCl₂.nEtOH:

A 3-liter autoclave, fully purged with N₂, was charged with 1.5 litersof purified kerosene, 112.5 g of commercially available MgCl₂, 163 g ofethanol and 5 g of Emasol 320 (a trademark for surfactants made byKao-Atlas Co., Ltd.). The mixture was heated with stirring, and stirredat 125° C. and 600 rpm for 20 minutes. The pressure of the inside of theautoclave was adjusted to 10 kg/cm².G with N₂. A cock of a stainlesssteel tube having an inside diameter of 3 mm directly connected to theautoclave and maintained at 125° C. was opened to transfer the mixturein the autoclave to a 5-liter glass flask (equipped with a stirrer)charged with 3 liters of purified kerosene cooled to -15° C. The amountof the mixture transferred was liter, and the time required for thetransfer was about 20 seconds. The resulting solid was collected bydecantation, and washed thoroughly with hexane to afford a carrier.Microscopic examination showed that the carrier was in the form ofcompletely spherical particles.

Preparation of a Ti-containing catalyst component:

A 300 ml glass flask was charged with 150 ml of TiCl₄, and 7.5 g of thesolid obtained as described in the foregoing section suspended in 15 mlof purified kerosene was added with stirring at 20° C. Then, 1.83 ml ofethyl benzoate was added, and the mixture was heated to 100° C. Themixture was stirred at 100° C. for 2 hours, and then the stirring wasstopped. The supernatant liquid was removed by decantation, and further150 ml of TiCl₄ was added. The mixture was stirred at 110° C. for 2hours. The solid portion was collected by hot filtration, and washedthoroughly with hot kerosene and hexane. The resulting titaniumcontaining catalyst component containing 4.4/ by weight of Ti, 59.0% byweight of Cl, 19.0% by weight of Mg and 13.0% by weight of ethylbenzoate as atoms. The catalyst component was in the form of sphericalparticles having a specific surface area of 207 m² /g, an averageparticle diameter of 13 microns, and a uniformity coefficient of 2.75.

Drying of the titanium catalyst component:

A suspension of 3 g of the catalyst component in 30 liters of hexane wastaken into a 300 ml flask fully purged with nitrogen. The flask wasplaced in a bath kept at 25° C., and a stream of nitrogen was passedthrough it for 30 minutes. The resulting titanium catalyst component wasa solid powder having good flowability. By analysis, it was found tohave a hexane content of 20.6%.

Polymerization:

A 2-liter autoclave was charged with 0.75 liter of hexane, and theinside of the autoclave was fully purged with propylene. Then, 3.75millimoles of triisobutyl aluminum, 1.75 millimoles of ethyl anisate,and 0.0225 millimole calculated as Ti atom of the above catalystcomponent were fed into the autoclave. H₂ was introduced in an amount of400 ml, and the polymerization system was heated to 60° C. propylene wasfed into the autoclave to maintain the pressure at 7 kg/cm². G, andpolymerized at 60° C. for 2 hours. After the polymerization, the slurrywas filtered to afford 215.9 g of a white powdery polymer having aboiling n-heptane extraction residue of 96.5%, an apparent density of0.42 g/ml and a melt flow index of 4.8. The polymer was in the form ofspherical particles having an average particle diameter of 330 micronsand a uniformity coefficient of 2.75. Concentrating the solvent layerafforded 4.6 g of a solvent-soluble polymer.

COMPARATIVE EXAMPLE 4

The titanium catalyst component before drying which was obtained inExample 7 was dried in the same way as in Example 7 except that thedrying time was changed to 4 hours. The resulting catalyst component hada hexane content of 0.3%.

Polymerization:

Propylene was polymerized under the same polymerization conditions as inExample 7. The results are shown in Table 2.

EXAMPLE 8

Tetraethoxysilane (0.11 mole) was added dropwise at room temperature to0.1 mole of commercially available n-butyl magnesium chloride (n-butylether solvent). The mixture was stirred at 60° C. for 1 hour. Theresulting solid was collected by filtration, and washed fully withhexane. The solid was suspended in 30 ml of kerosene, and 0.02 mole ofethyl benzoate was added dropwise and treated at 60° C. for 1 hour. Thetemperature was lowered, and 200 ml of TiCl₄ was added. The mixture wastreated with stirring at 100° C. for 2 hours. The supernatant liquid wasremoved by decantation. Then, 200 ml of TiCl₄ was further added, and theresidue was treated at 100° C. for 1 hour. The resulting solid wascollected by hot filtration, and washed thoroughly with hot kerosene andhexane. The resulting titanium catalyst component contained 2.4% byweight of Ti, 62.0% by weight of Cl, 21.0% by weight of Mg and 7.4% byweight of ethyl benzoate as atoms. The catalyst component was in theform of granules having an average particle diameter of 12 microns and auniformity coefficient of 2.7.

Drying:

A suspension of 3 g of the titanium catalyst component in 30 ml ofhexane was taken into a 300 ml flask fully purged with nitrogen. Theflask was dipped in a bath maintained at 30° C., and nitrogen was passedthrough it at 30° C. for 90 minutes. The dried solid catalyst componenthad good flowability and contained 18.9% by weight of hexane.

Polymerization:

Propylene was polymerized under the same conditions as in Example 7using the catalyst component prepared as above. The results are shown inTable 2.

COMPARATIVE EXAMPLE 5

The drying treatment in Example 8 was performed at 20° C. under reducedpressure for 4 hours. The resulting dry solid contained 0.2% by weightof hexane.

Propylene was polymerized under the same conditions as in Example 7using the resulting dry solid catalyst component. The results are shownin Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Example                                                                       (Ex.) or                                                                            Amount of                                                                           Boiling       Amount of                                           Compara-                                                                            a white                                                                             n-heptane     a solvent-                                                                          Average                                       tive  powdery                                                                             extraction                                                                          Apparent                                                                              soluble                                                                             particle                                                                           Uniform-                                 Example                                                                             polymer                                                                             residue                                                                             density polymer                                                                             diameter                                                                           ty co-                                                                              Shape of                           (CEx.)                                                                              (g)   (%)   (g/ml)                                                                             MI (g)   (microns)                                                                          efficient                                                                           polymer                            __________________________________________________________________________    Ex. 5 178.3 97.3  0.37 3.7                                                                              1.7   115  1.4   Spherical                          Ex. 6 187.6 97.3  0.37 5.2                                                                              1.4   120  1.4                                      Ex. 8 198.7 94.2  0.41 6.3                                                                              6.1   300  2.3   Granular                           CEx. 4                                                                              155.0 95.5  0.40 5.9                                                                              2.5   --   --                                       CEx. 5                                                                              144.9 94.0  0.41 6.6                                                                              5.9   --   --                                       __________________________________________________________________________

What we claim is:
 1. In a solid titanium catalyst component for theproduction of olefin polymers or copolymers, comprising titanium,magnesium, halogen and an electron donor as essential ingredients andfurther containing an inert liquid hydrocarbon, the improvement whereinthe liquid hydrocarbon is present in an amount of, based on the weightof said component, about 1 to about 10% when said component has auniformity coefficient of at least 4, and about 1 to about 25% when saidcomponent has a uniformity coefficient of less than
 4. 2. The solidtitanium catalyst component of claim wherein said content of the inertliquid hydrocarbon is attained by subjecting a solid titanium catalystcomponent containing said inert liquid hydrocarbon to a dryingtreatment.
 3. The solid titanium catalyst component of claim 1 whereinsaid content of the inert liquid hydrocarbon is about 1 to about 6% byweight based on the weight of said solid titanium catalyst component. 4.The solid titanium catalyst component of claim 1 wherein thehalogen/titanium mole ratio is more than about 4, the magnesium/titaniummole ratio is not less than about 3, and the electron donor/titaniummole ratio is from about 0.2 to about
 6. 5. The solid titanium catalystcomponent of claim 1 wherein said inert liquid hydrocarbon is a memberselected from the group consisting of aliphatic hydrocarbons, alicyclichydrocarbons, aromatic hydrocarbons, and mixtures of at least two ofthese hydrocarbons.